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Even if you are not restuffing the paper caps, which is surprisingly easy to do I found, don't toss them out, save them for a future project or put them in a bag and keep them with the radio. I think that Kirk may be right about that chunk of cardboard being the remnant of an old box electrolytic cap, since there are no cans or mounts for cans on the chassis then they would have had to use something like that. The dogbone resistors are not especially trustworthy, code is read this way, Body End Dot, 1/4 Watt carbon comps of any type should be checked, and if more then 20% off changed for 1/2 Watt ones.
Regards
Arran
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Thanks Arran. Yes I save them and have used them from time to time to stuff. Just not stuffing them on this set.
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I've reached a point where I need some help on where to go next. SCHEMATIC LINK
My first question, does anyone know which position the band lever switch should be in for broadcast (this is a zenith 8s359) There are 4 positions for the lever, LEFT>LEFT CENTER>RIGHT CENTER>RIGHT.
Tubes (except the indicator 6U5) and pilot lamps light up but I'm getting no sound. I do get a little static when probing some of the voltages. I've recapped all caps and changed out many of the resistors. I've checked the various coils and they all seem to have good continuity. Power transformer is good and my voltages look as follows:
[Image: https://www.dropbox.com/s/rye39ajsh7vxq9....jpg?raw=1]
I get a little static from the speaker when my probe is on the 6F5G plate (pin 4 rather than pin 3 noted incorrectly in my chart).
With the indicator tube out of the socket I get the following voltages in the indicator socket.
[Image: https://www.dropbox.com/s/lortw6ofkl4oyo....jpg?raw=1]
Appreciate thoughts on something to check next. Thanks!
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City: Roslyn Pa
>Appreciate thoughts
It's broke!
Voltages look pretty good. The output stage on this thing is sort of counter intuitive as the control grid of the 6AC5 is positively driven from the cathode of the 6P5. Should get a loud buzz when touching the cap of the 6F5. Have you checked the 6P5 and 6AC5? Do you have a signal tracer?
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
(This post was last modified: 03-15-2018, 08:54 PM by Radioroslyn.)
Posts: 5,088
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Tubes tested good. I will touch the 6F5 cap next time out to the shop. No tracer here but do have a sig gen with audio modulation.
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The photos of that socket look identical with one I did, and yes, much cursing was involved on my end also, but it was well worth the effort! I actually kind of miss it. The most frustratingly satisfying enjoyment one could ever hope to have... 
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State, Province, Country: OR
Yes Terry, I do get a buzz in the speaker when touching the 6F5 grid and if I put an audio tone signal on that grid I get tone from the speaker.
With a second radio I hear the oscillator at around 1050 when the zenith is tuned to about 600. Moving the zenith tuner back and forth A few hertz changes the sound in the second radio. And that confirms that the broadcast position for the band switch lever is left center.
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Ok both indications are good. Next take your signal generator and inject a modulated signal @ 455kc into the grid cap of the 6K7. Should hear signal in spkr if all is well. Then inject the 455kc signal into the grid cap of the 6A8. Again should hear tone in the spkr. Adj the output of the generator's output so you a just barely can hear it in the spkr. Adjust the IF trimmers for max output. If any of the IF trimmers don't have much of an effect you may have a bad IF transformer, but you know what to do in that case [Image: http://philcoradio.com/phorum/images/smi...n_clap.gif]. Will you be headed east in May??
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 5,088
Threads: 270
Joined: Nov 2012
City: Wilsonville
State, Province, Country: OR
No sound with modulated 455kc at either the 6k7 or 6A8 grid injection. Both the primary and secondary of the IF transformer show about 8 ohms so they do not seem to be open.
Yes am planning to be at K-town.
Posts: 7,285
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Joined: Dec 2009
City: Roslyn Pa
Ok, So remove the 6J5 and connect your audio signal the pin 5 of the 6J5 socket. Should hear your audio signal and it will be controlled by the volume control. May have a bad connection on the tone switches or a short in some of that rubber wire.
Be good to see you in May!
Terry
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 5,088
Threads: 270
Joined: Nov 2012
City: Wilsonville
State, Province, Country: OR
6J5 tube pulled, audio signal connected to pin 5 of 6J5 socket but get no sound.
Put audio signal back on thr 6F5 grid and do hear tone.
Yes will be great to see you aond the rest of the Philco gang.
In the course of doing this check I realised that I had miswired the connection from the 6F5 grid to the volume wiper arm. Fixed that but still no sound when making the above check with the 6J5 tube pulled.
Posts: 7,285
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Joined: Dec 2009
City: Roslyn Pa
Ok, Check your volume control connections for shorts to the chassis. Check both C12's to be sure that there isn't a wiring error.
How it works is that the audio signal from the detector is at the bottom of the 2nd IF transformer and is connected the junction of R7 and R8 (avc line). Goes thru C12 to the left side of the volume control. Audio signal goes from the left to the right side of the volume control. The wiper taps off the audio and connects it to the input (grid cap of the 6F5) thru C12 (the other C12).
We connected an audio signal to the inputs at the 6P5 and 6F5 and all was well. But when we connected the audio signal to output of the detector we got zip. So something between the left side of the volume control and the grid cap of the 6F5.
Happy Hunting!!
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
Posts: 5,088
Threads: 270
Joined: Nov 2012
City: Wilsonville
State, Province, Country: OR
03-19-2018, 01:30 AM
OK thanks Terry, I'll do some sluething...
Posts: 5,088
Threads: 270
Joined: Nov 2012
City: Wilsonville
State, Province, Country: OR
The good news is I now have broadcast playing! The bad news is I'm still not sure where the short is but have narrowed it down. In poking around I found that the two ends of the volume control pot showed a dead short when I checked resistance. I looked for a mistake in my wiring but could not locate it. In checking around the R2 resistor in the tone switch assembly I pulled the 9A Alto switch into the "out" position and that solved the short across the volume pot. Just for the heck of it I powered up and found that I now had broadcast playing, a little hum but not bad. At least I'm closer. More checking....
Posts: 7,285
Threads: 268
Joined: Dec 2009
City: Roslyn Pa
Gee your a regular Sherlock Ohms!!!! 
I'm sure you'll find what's what.
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
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